1. Field of the Invention
The present invention relates generally to an improved integrated circuit design system, and in particular, to a method for modifying an integrated circuit design for manufacture. Still more particularly, the present invention relates to a method, system, and computer usable program code for equation based retargeting of design layouts.
2. Description of the Related Art
Modern day electronics include components that use integrated circuits (ICs). Integrated circuits are electronic circuits formed using Silicon as a substrate and by adding impurities to form solid-state electronic devices, such as transistors, diodes, and resistors. Commonly known as a “chip”, an integrated circuit is generally encased in hard plastic. The components in modern day electronics generally appear to be rectangular black plastic pellets with connector pins protruding from the plastic encasement.
Circuit designers use a variety of software tools to design and test electronic circuits that accomplish an intended task. For example, a digital circuit may be designed to accept digital inputs, perform some computation, and produce a digital output. An analog circuit may be designed to accept analog signals, manipulate the analog signals, such as my amplifying, filtering, or mixing the signals, and produce an analog or digital output. Generally, any type of circuit can be designed as an IC.
Once a design layout, also referred to simply as a layout, has been finalized for an IC, the design is converted into a set of masks for lithography. A set of masks for lithography is one or more masks for lithography. During manufacture, a Silicon wafer is exposed to light or radiation through a set of masks to form microscopic components of the IC.
A layout includes shapes that the designer selects and positions to achieve a design objective. The objective is to have the shape—the target shape—appear on the wafer as designed. However, the shapes may not appear exactly as designed when manufactured on the wafer through photolithography. For example, a rectangular shape with sharp corners may appear as a rectangular shape with rounded corners on the wafer.